diff --git a/Assets/Tests/InputSystem/APIVerificationTests.cs b/Assets/Tests/InputSystem/APIVerificationTests.cs
index 502279c8da..03fd7e5275 100644
--- a/Assets/Tests/InputSystem/APIVerificationTests.cs
+++ b/Assets/Tests/InputSystem/APIVerificationTests.cs
@@ -243,12 +243,9 @@ public void API_MonoBehavioursHaveHelpUrls()
         var monoBehaviourTypes = typeof(InputSystem).Assembly.ExportedTypes.Where(t =>
             t.IsPublic && !t.IsAbstract && !IgnoreTypeForDocsByName(t.FullName) && !IgnoreTypeForDocsByNamespace(t.Namespace) &&
             typeof(MonoBehaviour).IsAssignableFrom(t));
-        var monoBehaviourTypesHelpUrls =
-            monoBehaviourTypes.Where(t => t.GetCustomAttribute<HelpURLAttribute>() != null)
-                .Select(t => t.GetCustomAttribute<HelpURLAttribute>().URL);
-        var monoBehaviourTypesWithoutHelpUrls =
-            monoBehaviourTypes.Where(t => t.GetCustomAttribute<HelpURLAttribute>() == null);
 
+        var monoBehaviourTypesHelpUrls = monoBehaviourTypes.Where(t => t.GetCustomAttributes<HelpURLAttribute>().Any()).Select(t => t.GetCustomAttributes<HelpURLAttribute>().First().URL);
+        var monoBehaviourTypesWithoutHelpUrls = monoBehaviourTypes.Where(t => !t.GetCustomAttributes<HelpURLAttribute>().Any());
         Assert.That(monoBehaviourTypesWithoutHelpUrls, Is.Empty);
         Assert.That(monoBehaviourTypesHelpUrls, Has.All.StartWith(InputSystem.kDocUrl));
     }
diff --git a/Assets/Tests/InputSystem/DocumentationBasedAPIVerficationTests.cs b/Assets/Tests/InputSystem/DocumentationBasedAPIVerficationTests.cs
index 7c6c1cc9c9..1b0fb6f378 100644
--- a/Assets/Tests/InputSystem/DocumentationBasedAPIVerficationTests.cs
+++ b/Assets/Tests/InputSystem/DocumentationBasedAPIVerficationTests.cs
@@ -127,7 +127,7 @@ public void API_MonoBehaviourHelpUrlsAreValid()
             typeof(MonoBehaviour).IsAssignableFrom(t));
 
         var monoBehaviourTypesWithHelpUrls = monoBehaviourTypes
-            .Where(t => t.GetCustomAttribute<HelpURLAttribute>() != null);
+            .Where(t => t.GetCustomAttributes<HelpURLAttribute>().Any());
 
         var brokenHelpUrlErrors = new StringBuilder();
 
@@ -135,7 +135,8 @@ public void API_MonoBehaviourHelpUrlsAreValid()
         foreach (var monoBehaviorTypeWithHelpUrl in monoBehaviourTypesWithHelpUrls)
         {
             // Get url
-            var url = monoBehaviorTypeWithHelpUrl.GetCustomAttribute<HelpURLAttribute>().URL;
+            var test = monoBehaviorTypeWithHelpUrl.GetCustomAttributes<HelpURLAttribute>();
+            var url = test.FirstOrDefault()?.URL;
 
             // Parse file path and anchor.
             var path = url.Substring(InputSystem.kDocUrl.Length);
diff --git a/Packages/com.unity.inputsystem/CHANGELOG.md b/Packages/com.unity.inputsystem/CHANGELOG.md
index c7360c52a6..374d6fd583 100644
--- a/Packages/com.unity.inputsystem/CHANGELOG.md
+++ b/Packages/com.unity.inputsystem/CHANGELOG.md
@@ -13,6 +13,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 - Fixed auto-save not working for Input System actions in Project Settings when both the Project Settings and Input System Actions windows were open [UUM-134035](https://jira.unity3d.com/browse/UUM-134035)
 - Improved New Input System warning dialog, Native Device Inputs Not Enabled [UUM-132151].
 - Fixed caching for InputControlPath display name [ISX-2501](https://jira.unity3d.com/browse/ISX-2501)
+- Fixed editor closing and not saving the input asset when clicking cancel in the dialog prompt [UUM-134748](https://jira.unity3d.com/browse/UUM-134748)
 
 ### Changed
 
diff --git a/Packages/com.unity.inputsystem/InputSystem/Editor/UITKAssetEditor/InputActionsEditorWindow.cs b/Packages/com.unity.inputsystem/InputSystem/Editor/UITKAssetEditor/InputActionsEditorWindow.cs
index 9039007cb1..3dbd534b67 100644
--- a/Packages/com.unity.inputsystem/InputSystem/Editor/UITKAssetEditor/InputActionsEditorWindow.cs
+++ b/Packages/com.unity.inputsystem/InputSystem/Editor/UITKAssetEditor/InputActionsEditorWindow.cs
@@ -24,6 +24,7 @@ static InputActionsEditorWindow()
 
         private string m_AssetJson;
         private bool m_IsDirty;
+        private bool m_IsEditorQuitting;
 
         private StateContainer m_StateContainer;
         private InputActionsEditorView m_View;
@@ -333,11 +334,21 @@ private void DirtyInputActionsEditorWindow(InputActionsEditorState newState)
         private void OnEnable()
         {
             analytics.Begin();
+            EditorApplication.wantsToQuit += OnWantsToQuit;
         }
 
         private void OnDisable()
         {
             analytics.End();
+            EditorApplication.wantsToQuit -= OnWantsToQuit;
+        }
+
+        private bool OnWantsToQuit()
+        {
+            // Here the user will be prompted
+            bool isAllowedToQuit = CheckCanCloseAndPromptIfDirty(false);
+            m_IsEditorQuitting = isAllowedToQuit;
+            return m_IsEditorQuitting;
         }
 
         private void OnFocus()
@@ -362,16 +373,22 @@ private void OnLostFocus()
             analytics.RegisterEditorFocusOut();
         }
 
-        private void HandleOnDestroy()
+        /// <summary>
+        /// Shows a dialog when trying to close an input asset without saving changes.
+        /// </summary>
+        /// <param name="rebuildUIOnCancel">If true, reopens the editor window when user cancels.</param>
+        /// <returns> Returns true if you should allow the Unity Editor to close. </returns>
+        private bool CheckCanCloseAndPromptIfDirty(bool rebuildUIOnCancel)
         {
             // Do we have unsaved changes that we need to ask the user to save or discard?
-            if (!m_IsDirty)
-                return;
+            // Early out if asset up to date or editor closing.
+            if (!m_IsDirty || m_IsEditorQuitting)
+                return true;
 
             // Get target asset path from GUID, if this fails file no longer exists and we need to abort.
             var assetPath = AssetDatabase.GUIDToAssetPath(m_AssetGUID);
             if (string.IsNullOrEmpty(assetPath))
-                return;
+                return true;
 
             // Prompt user with a dialog
             var result = Dialog.InputActionAsset.ShowSaveChanges(assetPath);
@@ -379,14 +396,18 @@ private void HandleOnDestroy()
             {
                 case Dialog.Result.Save:
                     Save(isAutoSave: false);
-                    break;
+                    return true;
                 case Dialog.Result.Cancel:
-                    // Cancel editor quit. (open new editor window with the edited asset)
-                    ReshowEditorWindowWithUnsavedChanges();
-                    break;
+                    if (rebuildUIOnCancel)
+                    {
+                        // Cancel editor quit. (open new editor window with the edited asset)
+                        ReshowEditorWindowWithUnsavedChanges();
+                    }
+
+                    return false;
                 case Dialog.Result.Discard:
                     // Don't save, quit - reload the old asset from the json to prevent the asset from being dirtied
-                    break;
+                    return true;
                 default:
                     throw new ArgumentOutOfRangeException(nameof(result));
             }
@@ -394,7 +415,7 @@ private void HandleOnDestroy()
 
         private void OnDestroy()
         {
-            HandleOnDestroy();
+            CheckCanCloseAndPromptIfDirty(true);
 
             // Clean-up
             CleanupStateContainer();